Jump to content

Server Lease Renewal/Software Licenses

Our yearly server lease, software licenses, as well as hardware operating costs, ARE due Dec 4th, 2022. Our current donations have fallen far short of the funds we need to renew. Please remember the RennTech.org community is Member supported so please consider a donation to help...  THANK YOU!

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

Car Died On Track - Codes PO157, P0300, P0302, P0303

Recommended Posts

Hi All,


Have my 1999 911 at the track today. During the first session, car began misfiring, lost power, and eventually stalled (would have turned it off sooner, but had to get off line).


Codes pulled from Durametric are:


P0157 - o2 Sensor behind cat converter. Cylinder (4-6)

P0300 - Misfire damaging to cat. converter

P0302 - Cylinder 2 misfire damaging to cat. converter

P0303 - Cylinder 3 misfire damaging to cat. converter


Other things that may help:

1. Looks like there is oil coming from the AOS area (wet on the side of the cam adjuster) - the AOS only has 10K miles on it, but I know that does not mean anything

2. Looks like there is some oil towards the rear of the motor of the drivers side, coming from above, but nothing looks wet from the top

3. I did try to start it (probably dumb). It runs for a second, and turns off. It is running rough, but does not sound like there is a bunch of metal floating around


What's odd about the codes is that the o2 sensor code appears to be on the opposite side of where the misfiires are happening, which does not make sense unless they are unrelated codes which seem unlikely.


There are lots of threads with these same codes, ranging from bad o2 sensor (please, let that be it) to blown engines.


Where do I start to diagnose? I plan to pull the filter and drain oil to take a look, once the engine cools, but any further guidance would be great.

Link to comment
Share on other sites

  • Moderators

I think that the P0157 is where to look.  Normally, this is the code for the O2 sensor behind the main cat on cylinders 4-6 being shorted, the sensor itself failing, or the DME crapping out.   Obviously, the DME dying would stall the engine, but we have also seen this code when the main cat failed and broke up, both killing the sensor and causing an exhaust system blockage, which would also stall the car by backing exhaust gases up into the intake, which can also cause misfires.  I'd start by looking at the cat on that side.

Link to comment
Share on other sites

Thanks JFP


I pulled the screw on filter to check for any issues. Poured the oil into a cup, dipped a magnet in, and unfortunately it was covered in sand sized metal particles.


A little looking and a few larger pieces were found. So it is not looking good. Fortunately, I trailerd it down and it was the last event of the season, and I was not assigned a student this weekend so I got to go home early.


Over the next couple of weeks I'll drop the pan to see what I can see, but I imagine the motor will be coming out and will be replaced or potentially rebuilt depending on damage.


I checked the durametric for over revs. It showed 214. I'm not 100% sure when that occurred. Or what 214 represents. I had not checked for over revs since I purchased the car in April. I did have on not so great shift during the session, but it was a couple laps before I lost power, so it seems a little unlikely the shift caused damage.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.